discrimation (horizontal) vs sensitivity (vertical) As we age, we lose some hearing power and visual acuity, for physical reasons on the organs. As our brains

discrimation (horizontal) vs sensitivity (vertical) As we age, we lose some hearing power and visual acuity, for physical reasons on the organs. As our brains mature, they learn to not discrimate among certain "unimportant" sounds and colors. Adults can't lose the ability to disambiguate among novel language phonemes from foreign languages (as perfectly as kids can), and similarly they lose ability to distinguish similar colors that they learned are irrelevant. This isa tradeoff adaptation, so you can see a shadow gradient as single color instead of a complex spectrum, understand that traffic lights are showing the same signal despite variation in frequency, etc. On another level, very small children (babies) have poor color vision, because their eyes and brains are still missing basic development. So it's a curve: newborns have poor hearing and vision tha rapidly improves for a few years and then decays slowly, for both physical breakdown and for mental "optimization"